The invention concerns converter gearing, which comprises a gear rim, which is connected to the axis of rotation of a converter vessel and engages at least one drive pinion of the converter gearing, and at least one locking device, which can be swung in or out to engage with or disengage from the teeth of the gear rim and has the form of a locking arm, which is mounted on a horizontal shaft and is configured with teeth, wherein the shaft is supported in a terminal bearing, the locking arm can be nonpositively engaged with or disengaged from the teeth by active force elements, e.g., hydraulic cylinders, and the shaft is supported in the housing of the converter gearing by two eccentric bushes, which rotate freely, one within the other, at each end of the shaft, in such a way that an ideal engagement position of the interacting toothed regions of the locking device and the gear rim can be set by independent rotation of the eccentric bushes, and a clamping element for adjusting a low-backlash bearing is associated with each of the eccentric bushes and the bores which hold the eccentric bushes.
Converter gears are subjected to high and variable torques during the oxygen-blowing operation. These torques usually lead to extreme loads per unit surface area and thus to excessive wear of the teeth.
It is well known that the harmful loads can be significantly reduced by the use of a locking arm. The terminal toothing of the locking arm for locking engagement in the teeth of the gear rim on the converter vessel corresponds as a “negative form” to about 5 to 6 tooth spaces of the driven gear. The load thereby evenly distributed to a region of the toothing results in a significant reduction of the surface pressure on the toothing and thus a reduction of the wear caused by the surface pressure.
A disadvantage of this design is the required setting precision of the locking lever and its bearing, especially when two independent locking levers are installed. This means that even small deviations from the ideal engagement position can lead to extremely high forces and stresses and thus to faster wear of the gear rim and the locking arm teeth.
To avoid these consequences, use was made of the measure of machining the housing and locking arm bore together. To do this, it is necessary to preassemble the gear rim and locking arm in their optimum position in the housing, then to fasten them in place and, finally, to machine them together.
This not only results in high production costs, but also has the further disadvantage that subsequent replacement or readjustment of the locking arm is not possible due to the special machining sequence.
The document EP 1 022 482 A1 describes a device for locking an element of a kinematic chain on a casting ladle, which comprises a part with an area of relief-like elevations and depressions provided on its periphery, which are complementary to areas with relief-like depressions and elevations on the element to be locked, and a device, which is installed at the end of a locking arm, for moving the part between a passive position “disengaged” from the element to be locked and an active position, in which the elevated and depressed areas of the element and the part penetrate each other to lock the element in a predetermined position. Indicating devices for the element in the predetermined position with respect to its elevated and depressed areas and devices for indicating the position of the locking arm are also provided.
The document GB 809 683 A concerns an improvement of the adjustable bearings of bolts, shafts, and similar elements. It describes the possibility of being able to adjust the position of these elements in all radial directions. Eccentric bushes that can be rotated one within the other are used for this purpose. The inner bush holds the shaft, while the outer bush is mounted in the housing. This produces the required possibilities for adjusting the shaft in all radial directions.
To maintain an adjusted position in a locking device, the document GB 590 202 A proposes that the eccentrics be locked on conical, rotationally symmetric plates by an outer screw connection with a set bolt. It is readily apparent that this is an extremely expensive and complex arrangement that requires a considerably greater construction space.